This invention relates to a method and apparatus for applying thermal energy to biological luminal tissue whereby tissue is converted to a denatured protein substance to join tightly approximated luminal tissue segments, and, more particularly to a method and apparatus for reconstructing severed tissue, including vessels and ducts by use of a device which is inserted into the tissue to hold edges of the tissue in tight proximity while directing thermal energy onto the tissue to denature the protein substance therein.
Optical energy transformed to thermal energy has been used to convert biological tissue into a denatured proteinaceous substance for facilitating healing and wound closure. This healing technique is referred to generally as laser tissue welding. Examples of such is laser tissue welding methods are described in U.S. Pat. Nos. 4,672,969, 4,854,320, 5,002,051, and 5,140,984. These methods deliver optical energy to tightly approximated tissue in the vicinity of a wound. This application of thermal energy results in the denaturation of tissue protein including collagen, with disruption of the cell walls which allows the intra- and intercellular fluids to mix, additional heat further denatures this protein soup which binds together creating something akin to a "biological glue".
In many prior methods of optical energy wound closure, thermal energy is delivered through an optical fiber to the tissue being reconstructed. Typically, one end of the fiber is connected to a laser that supplies optical energy to the wound site. Another end of the fiber is typically spaced a predetermined distance from the tissue, the distance depending on the tissue type. A foot pedal or hand held device activates and deactivates the laser. The parameters such as intensity and duration of the optical energy are controlled so that substantially all of the tissue being heated is raised to a predetermined non-destructive temperature. The minimum predetermined temperature is one at which tissue is converted to a denatured proteinaceous substance. The maximum predetermined temperature is one at which water in the tissue boils.
Other methods known for healing and wound closure include suturing and stapling. These methods are also used in endo-surgery or minimally invasive surgery in combination with various types of scopes, such as endoscopes, laparoscope, arthroscopes, etc. These scopes along with other medical equipment are inserted by a surgeon through incisions in the patient and then moved to the wound area being repaired. The scope is connected to a monitor so that the surgeon can view the procedure while the surgery is being performed.
Laser tissue welding may be used in minimally invasive and open surgery to repair vessels; however, conducting certain minimally invasive and open operations using laser melding surgery can be unnecessarily tedious as the surgeon welds at successive points along the circumference of the vessel or duct. This welding process is complicated because the distal end of the optical media that directs the energy for the welding must be placed a predetermined distance to the tissue being reconstructed or the area being reconstructed. If the distal end of the media is not at the predetermined distance from the area being sealed or reconstructed, the tissue temperature would be outside the aforementioned predetermined temperature range for proper tissue fusion.
Critical to current tissue welding methods is the necessity to place edges of tissue being repaired in tight approximation. Placing the tissue edges in close or tight proximity allows the denatured tissue constituents to form an intercellular matrix resulting in tissue fusion.
Certain luminal tissue types are very difficult for the surgeon to access with current thermal sealing techniques. Consequently, to thermally seal certain organs and vessels, the surgeon may have to cut or displace other organs that are in the way. This can create complications and can be time consuming.
Another sealing technique such as the one disclosed in U.S. Pat. No. 4,892,098, to Sauer requires that a stent device be placed within the lumen of the tissue being sealed for support at a wound. A circular housing is then placed around the tissue and fed optical energy to seal the wound. The proper placement of this stent device and the set up of the circular housing can be time consuming and result in an inconsistent application of optical energy.